The Picasso contains a story (4)
I believe the answer is:
epic
'a story' is the definition.
(I have seen 'Heroic story' mean 'epic' so perhaps 'story' could also mean 'epic')
'the picasso contains' is the wordplay.
'contains' says the answer is hidden in the clue.
'EPIC' is hidden within 'the picasso'.
(Other definitions for epic that I've seen before include "Heroic; saga" , "of impressive proportions?" , "A long poem or book with adventurous theme" , "Exodus, say" , "Long poem, book, film" .)